Before reading, refer to this guide to understand the notation I use:
http://steamproxy.net/sharedfiles/filedetails/?id=196132827


Spell Speed:
While all spells fire at the same speed in-game (excluding charged spells), some spells have slower input speeds than others because of the presses required. For example:

[SER] is faster than SSS,
Since the player can press S, E, and R at the same time, while SSS takes three individual presses.

Inputs and Strokes
Each press of a key is called an input. Each motion of the hand (one press or a combination of presses at once) is called a stroke. It is possible for some commands (a particular way to input a spell) to have more inputs than strokes. Reducing strokes is the key to speeding up spells, as one stroke is around a fourth of a second long, accounting for lag and other conditions.

Most spells can be reduced to three tiers:

Speed one(slow) - These spells are three strokes long, and are usually the same key pressed three times(such as DDD). They are the slowest of the spells.

Speed two(Two-One)- These spells are a press of two keys, followed by a press of one key(Two strokes). These inputs can generally be buffered.

Speed three(Piano Roll)- These spells are three strokes, but each stroke is pressed very quickly(such as ASA). These spells can also be cast as Two-One.

Speed four(One Stroke) - These spells are cast in one stroke, and are the fastest of all spells.

Buffering
Buffering is pressing the same combination of keys in excess to compensate for any input misreads. A common example:

Pressing [S][A][S] may result in the [A] input getting lost occasionally. Buffering the spell would look like:
[SA][SA]. Notice that there are more inputs of [A], with less strokes, decreasing the chance of an input error. Also, even if buffering a certain command doesn't reduce strokes, it can still makes some inputs easier on the fingers, or add some unpredictabilty to your inputs, (such as with [QF]).

Note that the main goal in spell buffering is not necessarily to improve speed, but rather to correct mistakes in inputs. As in the former example, losing the lightning portion of a [SA]S can cost you the fight.

Now that the definitions are out of the way...

Instead of:
SAS or [SA][S]

Try:
[SA][SA]

As discussed before, using [SA][SA] instead of [SA][S] buffers the [A] and [S] input, as well as reduces the number of strokes to 2 instead of the usual three. Note that sometimes the input may result in [SAA] instead of [SAS], but the difference is negligible.
-----------------------------------
Instead of:

QSQ or SQS

Try:

[QFS]

Beginners tend to gloss over this. [QF] creates steam, which wets the opponent and causes damage, making it a good substitute for regular water. [QFS] is one stroke instead of the usual 3. Additionally, you can buffer it as [QFS][S], which can fix a lost [S] input. Note, however, that buffering this spell with [QFS][QFS] may result in the command being read as [SF] or [SQ] if you do not cast the spell fast enough.
-----------------------------------
Instead of:

<SRS or RSR> and <SFS or FSF>

Try:
[SR][SR] and [SF][SF]

This spell is similar to the [AS][AS] buffer from before, reducing the strokes to 2 and making up for a lost [S] input. When doing this buffer, beware of accidentally pressing [A] using your ring finger, as the positioning for [SF][SF] is similar to [AS][AS]. If needed, use your ring finger to input [S] instead of the middle finger.

Instead of:

DDD

Try:

[QRD] or [QDS]

This is one of the most important substitutions you can make, especially if you use rocks often. The [QRD] input compresses the slow 3 stroke command into a single stroke that does as much damage and pierces rock armor! To perform the shortcut, have the ring finger at [Q], the index finger at [R], and the thumb at [D]. However, this command is difficult to buffer and has an awkward finger placement. Use this shortcut only when you intend on bombarding the enemy with rocks. An alternate command is [QDS], another 1 stroke shortcut. This version sacrifices damage for great input speed and wetness. Note that both of these shortcuts also bypass the rock ward.
-----------------------------------

Instead of:

FFF or QQQ

Try:

[QF][F]

This shortcut has an interesting effect: The wetting effect of steam should be overriden by the effect of fire most of the time, making [QF][F] a faster and potentially more potent form of FFF. Alternatively, you can buffer the input as [QF][QF] or [QF][QF][QF] for the most unpredictable command in the game. Neither you nor the enemy will know whether to use a water ward, a fire ward, or a beam ward!

As of last patch, [QF][F] No longer works. Stick to FFF and QQQ.

Because buffering any input including [E] causes the input to be lost([E] cancels [E]), most of these spells cannot be buffered. Any instance where a command can be buffered will be noted.


Instead of:

EDD

Try:
[DEW]

As well as having a convenient name, the [DEW] command shortens the three stroke input to one stroke and gives the wall healing properties. Generally speaking, it is faster to create three [DEW] walls than to make one EDD wall. As two [DEW] walls equal one EDD wall, [DEW] is better than EDD. If you are retreating, however, is is better to use EDD.
------------------------------

Instead of:

RED or FED

Try:

[ERS] or [EFS]

Due to the way the keyboard is configured, RED and FED can only be performed as three inputs moves accurately.(Try pressing all three at once: nothing will come out). Due to this, the mine version of the walls , [ERS] and [EFS], is recommended. While retreating, when speed is everything, the difference between one stroke and three strokes is the difference between life and death.
------------------------------

Instead of:

QEQ

Try:

[QEF] or [QES] or [QEQE]

As with the QSQ fix, walls also benefit from replacing water with steam. However, if you need the knockback effect of water, you can use [QES]. Because of the position of the keys on the keyboard, [QE] is one of the few walls you can buffer with relative safety, if you're fast enough.

This guide is still a work in progress. If you have any suggestions for a spell shortcut, leave them in the comments.

Special thanks to the maker of the spell notation guide, who has helped a great deal with the guide.
http://steamproxy.net/sharedfiles/filedetails/?id=196132827

For more ways to defeat your foes, check out this guide:
http://steamproxy.net/sharedfiles/filedetails/?id=191429243#-1